Calling from one path to another virual path in same Azure App service?

Tanul 1,251

Team,

If we host 2 small api within same app service and provide their virtual path like this

Then, is it possible to enable calls between them through urls like this

http:// 127.0.0.1/site1 or http://localhost/site1

I can use the complete url but in that case unnecessary hops of api gateway or routers will come in the middle.

In my case, the request will only come to service sitting at wwwroot along with its token. Now, this service will redirect the call to site1(test1) service for validation process because site1 service manages token creation and validation process.

Can anyone let me know if it is possible.

Regards,
Tanul

Tanul 1,251 Reputation points

2021-03-17T13:37:54.817+00:00

@ajkuma , Hey ajay.. Hwz going. All well? If you get some time could you please help me on this issue.

Thank you. Take care.

Regards
Tanul

1 answer

Ryan Hill 25,666 Reputation points Microsoft Employee

2021-03-18T02:59:26.407+00:00

Hi @Tanul ,

You will need to use the public facing DNS name, e.g., https://yourapp.azurewebsites.net to https://youapp.azurewebsites.net/test1 as calls to localhost will fail with an exception. See https://github.com/projectkudu/kudu/wiki/Azure-Web-App-sandbox#local-address-requests

EDIT: If you're using virtual directories, then you should be able to use relative paths e.g. ~/test1; however, using the app service host name is recommended to avoid any issues.

Regards,
Ryan
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Tanul 1,251 Reputation points

2021-03-18T13:32:25.063+00:00

@Ryan Hill , thanks for sharing the details. But I’m unable to understand this line

except if another process in the same sandbox has created a listening socket on the destination port.

Does that mean running 2 api within same app service.

Ryan Hill 25,666 Reputation points Microsoft Employee

2021-03-18T17:38:51.493+00:00

Hi @Tanul , I jumped the gun a little early. I did update my response but let's step back a bit. To confirm, you asking about a virtual directory and not a virtual application, correct? If yes, virtual directory should be easily accessible as a relative path and both site/wwwroot and site/wwwroot/virtdir should run under the same w3wp process.

except if another process in the same sandbox has created a listening socket on the destination port

to me says if something like a nodejs process has port 3389 open, your MVC app can say https://localhost:3389/api/getdata is allowed from site/wwwroot.

Tanul 1,251 Reputation points

2021-03-18T22:46:03.953+00:00

@Ryan Hill , Hey Ryan.
So basically what I will do is I will host one golang application at a random port placed in site\wwwroot directory whose end point will be http://azurexxxxxx.something.com/

Next golang app will act as a validator which I will host in site\test1 folder of same app service at random port and run at path /test1.

Now client from outside can also reach to other app at this url: http://azurexxxxxx.something.com/test1

But, I want to make a call to test1 from my first golang app as well. So, in that case is it possible to make http call to some localhost url. Because if my first app calls second via complete azure url then unnecessary network hops will come in the middle.

When they both are in same app service can they call each other internally.

Regards
Tanul

Ryan Hill 25,666 Reputation points Microsoft Employee

2021-03-19T02:10:04.987+00:00

In your scenario @Tanul , /test1 and / lives on the same webspace so you should be good to request ~/test1 as a relative url to the root. Do let me know if you run into any issues though.

Tanul 1,251 Reputation points

2021-03-22T22:57:28.703+00:00

@Ryan Hill , Hello Ryan.. Thanks a lot for sharing. Day after tomorrow I will execute this task using Go app. Will confirm :)

Take care. Have a nice day

Regards
Tanul

Tanul 1,251 Reputation points

2021-03-23T22:11:32.067+00:00

@Ryan Hill , Hey ryan, I have tried but it is not working. The moment I hit the the virtual path i.e.

http://something.com/test1/validate/

It gives 404 page not found even though the api.exe is starting the moment I hit the url. I have also confirmed this through tasklist command by running in kudu. Then, I have ran the the curl command in the kudu console itself and it is returning correct results. But with curl command also I can’t put the complete virtual path. Only this one works

curl http://localhost:<port>/validate/

The structure of my folders is.

One api.exe is placed in site\wwwroot

Other one in site\wwwroot\test

Virtual Path ( set as Application) is

/test site\wwwroot\test

I have put the same exe in both the folders but the only one belonging to this folder site\wwwroot returning the results.

Then I have deleted the one placed in site\wwwroot still other one is not returning the results.

Tanul 1,251 Reputation points

2021-03-23T22:34:32.437+00:00

Web.config section for both files

<handlers> <add name="httpplatformhandler" path="*" verb="*" modules="httpPlatformHandler" resourceType="Unspecified" /> </handlers>

<httpPlatform processPath=".\Dev.exe" startupTimeLimit="60"></httpPlatform>

<handlers> <add name="httpplatformhandler" path="*" verb="*" modules="httpPlatformHandler" resourceType="Unspecified" /> </handlers> <httpPlatform processPath=".\OtherDev.exe" startupTimeLimit="60"></httpPlatform>

Ryan Hill 25,666 Reputation points Microsoft Employee

2021-03-25T16:12:47.8+00:00

Did you modify web.config yourself? Also, just confirm, /test1 virtual app is a golang app? What logs do you see from your app service when you hit /test1?

Tanul 1,251 Reputation points

2021-03-25T21:11:33.04+00:00

Hello.
Yes I've made my own web.config and it is a golang app. The web.config for virtual application(/test1) is shown below. Also tried with and without location

<?xml version="1.0" encoding="UTF-8"?> <configuration> <location path="." inheritInChildApplications="false"> <system.webServer> <handlers> <add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModuleV2" resourceType="Unspecified" /> </handlers> <aspNetCore processPath=".\OtherDev.exe" startupTimeLimit="60" stdoutLogEnabled="true" stdoutLogFile=".\logs\stdout" hostingModel="OutOfProcess" > </aspNetCore> </system.webServer> </location> </configuration>

Tanul 1,251 Reputation points

2021-03-25T21:14:47.61+00:00

The error is
HTTP Error 404.0 - Not Found
The resource you are looking for has been removed, had its name changed, or is temporarily unavailable.

Detailed Error Information:
Module AspNetCoreModuleV2
Notification ExecuteRequestHandler
Handler aspNetCore
Error Code 0x00000000
Requested URL https://golangtest:80/test/validate/
Physical Path C:\home\site\wwwroot\test\validate\
Logon Method Anonymous
Logon User Anonymous

Tanul 1,251 Reputation points

2021-03-25T21:17:59.867+00:00

Few more errors after enabling trace:

Tanul 1,251 Reputation points

2021-03-25T21:30:11.547+00:00

After giving this web.config

<?xml version="1.0" encoding="UTF-8"?> <configuration> <location path="." inheritInChildApplications="false"> <system.webServer> <handlers> <add name="httpplatformhandler" path="*" verb="*" modules="httpPlatformHandler" resourceType="Unspecified" /> </handlers>  <httpPlatform processPath=".\OtherDev.exe" startupTimeLimit="60"></httpPlatform> </system.webServer> </location> </configuration>

Note:- exactly same config is used in the root app i.e. placed in site\wwwroot and its working fine.

Tanul 1,251 Reputation points

2021-03-25T21:30:26.79+00:00

Getting these errors:

HTTP Error 500.19 - Internal Server Error
The requested page cannot be accessed because the related configuration data for the page is invalid.

Ryan Hill 25,666 Reputation points Microsoft Employee

2021-03-26T15:24:28.41+00:00

This request

Requested URL https://golangtest:80/test/validate/

Won't work because the hosted server isn't controlled by the user. localhost:80 should work, BUT your golang app needs to be listening on a separate port.

Tanul 1,251 Reputation points

2021-03-26T20:48:51.98+00:00

@Ryan Hill , But I'm not sending this request from my end. In my code the application is hosted at random port. And, the same application is working perfectly on default route i.e. /
My complete url is like this https://golangtest.appservice.xxxxxxx.com

This is the code I've written in which 1st condition will be successful if I use httpplatformhandler and 2nd one in case of AspnetcoremoduleV2.

if os.Getenv("HTTP_PLATFORM_PORT") != "" { port = os.Getenv("HTTP_PLATFORM_PORT") } if os.Getenv("ASPNETCORE_PORT") != "" { // get enviroment variable that set by ACNM port = os.Getenv("ASPNETCORE_PORT") }

golangtest is the name of my app service. In my understanding, any golang runs outofprocess. So, if we consider this diagram then 80 port is shown because of w3wp process

Tanul 1,251 Reputation points

2021-03-29T19:34:09.203+00:00

@Ryan Hill , Hey ryan, please correct me if I'm wrong. Is it allowed to have to have two different web.config. In such cases do we need 2 web.config or one. Do you have any samples. You can also share the one we use with self contained single binary .net core application. I know that same works with golang.

Ryan Hill 25,666 Reputation points Microsoft Employee

2021-03-29T22:12:03.993+00:00

Your virtual app is seen as a separate objects; see https://learn.microsoft.com/en-us/iis/get-started/planning-your-iis-architecture/understanding-sites-applications-and-virtual-directories-on-iis#about-sites-applications-and-virtual-directories-in-iis-7-and-above, so keeping two separate web.config is the way to go. If you run out of process, then port will be whatever krestrel is listening on.

There aren't any samples when it comes to virtual apps, as it's not really that common. I can try on my end, see what I come up with.

Regards,
Ryan

Tanul 1,251 Reputation points

2021-03-30T22:08:19.333+00:00

@Ryan Hill , i think there is some issue with the golang itself.

I have done a poc in which hosted one golang app at root folder and one .net framework V 4.7.1 api(framework dependent) in virtual app and both are working fine. Though I haven’t tried calling the
each other internally through this syntax ~/test. I’ll check it tomorrow.

Other than that, I have also tried a .net core api(self contained single binary exe) as virtual app but it did not work. Its swagger portal opened but with error popup. I’ll try to interrogate it once again.

At last, tried with golang as virtual app but received 404 not found

Let me know once you’ve any updates. Thank you. Take care.

Regards
Tanul

Tanul 1,251 Reputation points

2021-04-10T19:57:27.74+00:00

@Ryan Hill , Hey ryan. Trust you’re doing well. Did you get a chance to try making virtual apps at your end.

Ryan Hill 25,666 Reputation points Microsoft Employee

2021-04-11T00:18:59.3+00:00

Hi @Tanul , my sincerest apologies. I haven't had a chance yet, but I should have some time in the next day or so.

Ryan Hill 25,666 Reputation points Microsoft Employee

2021-04-16T18:19:15.127+00:00

Hi @Tanul I've discussed with the product team and the recommendation is to use the hostname to avoid any issues. The platform doesn't have any mechanisms in place for making clean calls such as this.

I've updated my answer above indicating this as well.

Tanul 1,251 Reputation points

2021-04-20T18:34:54.003+00:00

@Ryan Hill , Hey ryan, hostname means complete url correct?

Like website.appservice.something.azure.com

Ryan Hill 25,666 Reputation points Microsoft Employee

2021-04-20T19:18:40.34+00:00

It will be something like https://youapp.azurewebsites.net/api/go-api-endpoint @Tanul .

Tanul 1,251 Reputation points

2021-04-21T21:42:47.293+00:00

@Ryan Hill , Hmm complete uri. Done brother. will do like this. .net core apps are working as the way you've suggested before. For golang apps I'll follow the complete uri approach.

Thanks a lot mate. Take care.. Have a great day.. :)
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Calling from one path to another virual path in same Azure App service?

1 answer

<httpPlatform processPath=".\Dev.exe" startupTimeLimit="60"></httpPlatform>